Gene Transfer Methods
Gene transfer methods, utilizing recombinant DNA technology, differ for animals and plants; while in animals, DNA is injected into either the pronuclei of embryonic cells (or fertilized egg) or the embryo stem (ES) cells, in plants cells, protoplasts or meristematic embryonic tissues are used. This basic difference is due to the availability of the techniques of in vitro fertilization (IVF) and embryo transfer (ET) in animals and those of protoplast culture and regeneration of protoplasts into whole plants in higher plants. IVF andET is not successful in plants (instead embryo culture is possible). Similarly cell culture and regeneration of a cell into a whole animal is not possible in higher animals, In view of this, gene transfer methods for animals and plants will be discussed separately.